


The Key To It All

by Useless19



Series: MegOP Week [7]
Category: Transformers - All Media Types, Transformers: Prime
Genre: (In chapter 2), Bodyswap, M/M, One Shall Rise AU, Sticky Sexual Interfacing
Language: English
Status: Completed
Published: 2020-01-11
Updated: 2020-01-11
Packaged: 2021-02-27 04:53:57
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 2
Words: 11,328
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22211347
Author URL: https://archiveofourown.org/users/Useless19/pseuds/Useless19
Summary: "Are you trying to tell me that Unicron’s fading flash —somehow— managed to perform a perfect spark transfer?" Ratchet said, voice dripping with disbelief.For MegOP week, Day 7: Free theme (bodyswap)
Relationships: Megatron/Optimus Prime, Megatron/Orion Pax
Series: MegOP Week [7]
Series URL: https://archiveofourown.org/series/1593355
Comments: 17
Kudos: 153
Collections: MegOP Week 2020





	1. Chapter 1

**Author's Note:**

> I wish I'd kept _Reformat_ for this, but c’est la vie. Have another _One Shall Rise_ AU.
> 
> Happy MegOP week everyone! It's been a blast.

The Ground Bridge lit up. Jack waited with everyone else at the entrance, his sneaker catching on the edge of the Autobot symbol carved into the floor. He squinted into the blinding blue and was just able to make out a handful of silhouettes in the distance.

Wait, that was _five_ figures walking down the Bridge. Megatron was still with them.

"Back up, kids," Fowler said, tugging Miko by the shoulder. He’d seen the Decepticon too. "We don’t want him getting any ideas."

June steered Raf towards the stairs and Jack followed. The Bridge vanished, leaving the slight ringing in Jack’s ears it always did.

"Optimus," Ratchet said, relief clear in his voice, "I am glad you made it back."

"Indeed, Ratchet," Megatron said. He grabbed Optimus by the smokestack when he tried to take a step forward. "Do not."

"You used to be fun, once," Optimus grumbled. "How do you expect me to contact Soundwave without access to your communications?"

"What’s going on?" Ratchet asked, eyes narrow and stance shifting into something combative. "Optimus?"

"We got separated at Unicron’s spark chamber," Arcee filled in. She was watching Optimus with a deep look of suspicion. "And… this happened." She waved at Optimus and Megatron.

Megatron, who was speaking in Optimus’s slow, measured tones, and Optimus, who was _smiling_ as he looked around the base as though he hadn’t seen it properly before.

"Have you got all switched up?" Miko asked a second before Jack completed his thought.

"Are you trying to tell me that Unicron’s fading flash — _somehow_ — managed to perform a perfect spark transfer?" Ratchet said, voice dripping with disbelief.

"You’re the medic, you tell me," Optimus said.

He sounded so much like Megatron that Jack could believe it. Megatron was frowning at Optimus in mild disapproval as Megatron-in-Optimus’s-body stalked toward Ratchet and the computer setup.

"Man, this is going to get confusing," Miko said. "We need new names for them."

"We do not need new names because this can’t be happening," Ratchet snapped. "I don’t care what delusions dark energon has induced in you Optimus, this ends now."

"Ratchet —" Megatron started.

"Not another word from you!" Ratchet levelled his finger at Megatron.

Megatron’s face fell and now Jack was more convinced than ever — there was no way even a really committed Megatron could’ve pulled that off. Ratchet caught himself and stepped back, looking a bit guilty from shouting at Optimus.

"Get in the scanner," Ratchet sighed. "If I’m comparing sparks I want a clean image."

Optimus-in-Megatron’s-body nodded and walked over to the big medical scanner. Raf quietly opened his laptop as Megatron-in-Optimus’s-body started to poke at the computer. Arcee and Bee kept their blasters trained on him, while Bulkhead went to help Ratchet and Meg— _Optimus_ at the scanner.

"I’m surprised you can get anything done on this… hybrid technology," Megatron commented snidely. He fumbled the keyboard and hissed a curse in a language Jack couldn’t understand. " _Built more useful for data transfer_ , my —"

"Cut the commentary," Arcee interrupted.

Megatron snorted — a weird sound to hear from Optimus's body — and keyed in a long string of Cybertronian characters. Raf made a quiet, interested noise behind Jack and started furiously typing.

The connection activated.

"Soundwave, this is Optimus Prime." Megatron’s impression was uncanny. "We have Megatron in custody. We will begin negotiations for his return once the aftermath from defeating Unicron has been remedied."

A string of sharp beeps and screeches — not dissimilar to a dial-up connection — came in reply. It must’ve meant something to Megatron though, and Raf looked up curiously.

"I will contact you again within two hours," Megatron said, then cut the connection and gave Arcee a smug look.

"Wow, you sounded just like him," Miko said.

"I am more familiar with this frame above all others, save my own," Megatron said, with a smirk Jack didn’t want to think about.

"Yeah, great. Now step away from the computer." Arcee gestured with her blasters as she spoke.

Still smiling, Megatron moved away.

"Well, they’re telling the truth," Ratchet said grimly. "Nothing can replicate a spark-signature that precisely."

"So how do we get them back to normal?" Jack asked. "Can’t you just… swap back?"

"Even if I had the tools for a spark transfer it isn’t something you want to be cavalier with," Ratchet said.

Megatron scoffed, then snarled when Optimus’s facemask slammed shut, surprising him. He forced it open with both hands.

"We have all the equipment you could need on the _Nemesis_. I’m sure Knock Out would be persuaded to make an attempt if you’re too apprehensive."

"You're not taking Optimus _anywhere_ ," Ratchet snapped. "And you're definitely _not_ letting that hack you call a medic touch him."

"Then we are at an impasse," Megatron said, but he looked like he was enjoying himself despite the stalemate.

"Either Unicron or the Matrix of Leadership was likely responsible for our predicament," Optimus said, "it is likely the solution is just as mystically inclined."

" _Optimus_ ," Ratchet groaned. "There is a rational, _scientific_ explanation and there will be a _rational_ and _scientific_ solution. There always is!"

There was a _screech_ of metal then a _snap_. Megatron tossed Optimus’s facemask to the ground.

"That’s enough of that," he said.

Optimus narrowed his eyes, then unlatched the massive cannon on his arm and handed it to Ratchet.

"See to it that this is put somewhere safe," Optimus said. "I believe it would also be a good idea for the humans to leave as well."

That sounded good to Jack. He grabbed Miko by the elbow when it looked like she was going to protest and headed for the exit.

"Wait," Megatron said. He pointed at Jack. "That human, he stays. He’s connected to this, I can feel it."

Ratchet bristled. "You’re not in a position to be making demands, Megatron."

Megatron ignored him and looked at Optimus. "You gave him something. Something to do with the Matrix."

"I did," Optimus said. "It may hold some answers to our predicament. Jack, may I have the key back?"

As weird as it had been to be handed the key by Optimus the first time around, it was even weirder to be handing it back to Megatron’s vicious claws, despite Optimus being in control.

"The key to Vector Sigma," Megatron said, something like awe in his voice. "And you trusted it to a human, Optimus? Clever."

"Is that everything? Can I go now?" Jack asked.

"No," Megatron said, "it's not the key I sense, it's _you_."

Jack hugged himself as all the ‘Bots _except Optimus_ started arguing against that. He met Optimus’s slitted red eyes and knew he wasn’t done.

Jack nodded. Optimus gifted him a proud smile that looked all wrong, yet strangely familiar on Megatron’s face.

"I believe I know what the issue is," Optimus said, drawing everyone’s attention. "Could I have a moment alone with Jack and Megatron?"

"You can’t seriously be thinking of leaving Jack alone with _him!_ " June shouted.

"Mom, it’ll be fine."

"I will keep Jack safe," Optimus promised. "And Megatron will do him no harm. If what I suspect is true, then we will need Jack’s input to solve our predicament."

It was hard to argue with Optimus — though June and Ratchet gave it a good shot — and soon Jack was left alone with Optimus and Megatron.

"What’s this about, Optimus?" Megatron asked.

"Explain how you can sense Jack."

Megatron shut his eyes. "He’s… magnetic. He calls to the Matrix and I can locate him through it even if I shut off my sensors." He opened his eyes to glare at Optimus. "What. Did. You. Do?"

"Jack, please come up here." Optimus waited until Jack had clambered back up the gantry — it still only put him at chest-level with Optimus and Megatron. "You should hear this too.

"When I gave Jack the key to Vector Sigma, it was more than the physical handover of the key itself. There are security measures inbuilt to the Matrix and its associated sanctuaries, to prevent them from being subject to misuse from unworthy forces."

"Those unfortunate enough to not have lived the life of a sheltered archivist," Megatron added snidely.

"Those who would use the Matrix for subjugation," Optimus said. "Jack has become a guardian of some of those secrets — ones I, myself, do not necessarily know. Jack, can you try to focus and tell us what you think will solve our predicament?"

So, hey, no pressure or anything.

Jack rubbed his hands on his jeans, sharply aware that he wasn’t even seventeen yet and was just a human, compared to these thousands of years old giant alien robots. What did _he_ have that they didn’t?

"Jack, relax," Optimus said — the careful sensitive tone he was aiming for coming out all wrong in Megatron’s voice. He handed the key back. "Listen to it, what is it telling you?"

Considering the amount of size-shifting it did, the key was weirdly light. It felt alive in Jack’s fingers, like the hood of a running car, and he was halfway convinced that he’d give someone a hell of a static shock if they tried to take it.

 _Listen to it_ , Optimus had said. Feeling foolish, Jack lifted the key to his ear. There was a soft hum, like a tuning fork that had just been struck, but no words or anything else useful.

What had Megatron said? He could feel it like a magnet? Jack laid the key flat on his palm. It didn’t helpfully spin and point in a useful direction or anything.

"Uh, Optimus?" Jack said.

"Concentrate, Jack," Optimus said calmly.

"This is a waste of time," Megatron said. Privately, Jack agreed with him.

"Close your eyes, Jack, and listen to me," Optimus said. Jack did so, feeling even more foolish. "Picture the key in your mind. Think about its shape, how it feels in your hand."

Jack tried to, he really did. But every time he tried to focus on the key’s silvery geometric pattern and blue glow, it changed. Frustrated, he opened his eyes and looked at Optimus again.

"I can’t," Jack admitted. "Is there something that makes it hard to remember? I know what it looks like but I can’t hold the shape of it in my head."

"What do you see instead?" Optimus asked, patient as always.

Jack closed his eyes again and had the difficult task of trying to picture one thing while focusing on the other. For a moment, the key was perfectly drawn in his mind’s eye, then it shifted again.

"Uh, it’s gold?" Jack said. "Like a figure eight around a blue crystal thing?"

"The Matrix," Optimus said. "Megatron, may I see it?"

"In front of a human?" Megatron said, surprised. "I suppose it is _your_ spark chamber."

Megatron’s windscreens flipped up and his chest parted. He’d angled away from Jack somewhat, but he could still see the solid metal shift aside like it was nothing. It was really weird, sometimes Jack almost forgot that the Autobots and Decepticons were machines as much as they were people.

Light spilt out, blueish and lilac against Optimus. Optimus frowned, even going so far as to duck down and get a closer look.

"It appears to have gone inert," Optimus said.

Megatron snorted. "I can _feel_ it, even if it hasn’t bonded to my spark. It’s — I can feel it, Optimus."

"It still looks dull compared to when I first received it," Optimus said. "With Jack’s connection to the key highlighting the Matrix, it may be that we have to return it to Vector Sigma to revitalise it."

"And then what?" Megatron snapped, shutting his spark chamber with a solid _thunk_ like a car door being slammed. "Will it decide to transfer our sparks back for the same nonsense reason it switched them to begin with? Forgive me if I’m distrusting of these Primely relics."

Frustration passed over Optimus’s face and his sword shot out of his arm, scratching the floor. Megatron laughed.

"You want your frame back," Optimus said curtly, forcefully pushing his sword back. "Can I rely on your selfishness that far?"

"If that’s how you wish to phrase it, yes," Megatron said, "I want my frame back more than I want the Matrix."

"More than you want me dead?"

"... Yes."

Optimus sighed. "My memories are fading. I am Optimus Prime, but only the Matrix has made me so. Without the Matrix of Leadership — without it fully charged — I am only Orion Pax."

He looked at Jack, who realised that he should be paying attention because he might have to tell the others later. As cool as it was to be trusted with Optimus’s secrets, it was really scary and stressful to know that Jack was the only one who could do something about it.

"I believe the Matrix, assisted by Unicron’s fading flash and the shard of dark energon within your spark, performed this spark transfer to protect my identity," Optimus continued. "So long as the Matrix does not have to spend energy on accessing my memories from within itself and can instead shortcut the process by using your spark and processor, I can survive for a while longer."

"Why?" Jack asked. "I mean, you’re in a war against Megatron. The Matrix knows that, right?"

"It’s protecting itself," Megatron said, rolling his eyes. "If Optimus had lost his memories then he wouldn’t have been able to fight and I would have put my sword through his spark after we defeated Unicron. That would have destroyed the Matrix."

"And it knows you want your body back first," Jack said. "Okay, that makes more sense."

"So our path leads to Vector Sigma," Megatron said.

"If you can provide a Space Bridge to Cybertron, Megatron, then Jack will be able to lead us to Vector Sigma," Optimus said.

"And you can't just tell us exactly where it is… why?" Megatron asked. "Why risk a human in Cybertron's poisonous atmosphere?"

"Because the location of Vector Sigma is not fixed," Optimus replied. "I no longer have a full connection with the Matrix, and your spark has not properly bonded to it either. Jack was chosen, he can find the way."

"How _useful_."

"I will let the others know they can return," Optimus said.

Megatron cut him off. "There's no rush. We might as well rule out a sparkmerge as a solution now, while we have _some_ privacy. And I've always wondered what my spike feels like from the other side," Megatron said, in a tone that could only be described as _flirty_ — even with Optimus's voice.

Then Jack parsed what he'd actually said and had to forcibly stop himself trying to figure out what he meant.

Was he talking about sex? Giant alien robot _sex?_

"Not in front of Jack," Optimus said, which only confirmed it.

"We'll be occupied with travel and a fix soon enough," Megatron said, leaning against Optimus. "Why not take this chance to… reacquaint ourselves? How often will we get this opportunity?"

"There is a reason for that. We are on different sides of a war."

"And right now we’re working together."

"We may not have time."

You know, _no_ was a perfectly good word that Optimus _wasn't using_. And now Jack turned his back — despite promises he'd made to keep an eye on Megatron — because Megatron's hand had disappeared between him and Optimus and Optimus was glancing around guiltily.

" _Megatron_." Optimus sounded strained.

"Optimus." Megatron didn't.

Jack heard the sound he associated with transformation, but when he glanced back they were both still in robot form. Except Megatron’s hand was —

 _Nope_.

Nope nope nope.

Jack called Arcee. She picked up on the first ring.

" _Jack! Are you okay?_ "

"Fine," Jack hissed, hoping to avoid drawing attention from the busy robots in the room, "but I’m not going to be if I have to watch Optimus and Megatron bang!"

" _I’m on my way._ "

Jack hung up and silently excused himself to go and wait by the room entrance. Soon — though it took longer than Jack would’ve like — Arcee and the other Autobots reappeared. Well, most of the other Autobots. Bulkhead had vanished, as had Raf and Miko. Jack guessed Bulkhead was keeping them away from Megatron by taking them home.

June and Agent Fowler were still here though.

Fortunately, the Autobots coming back made Megatron back off and Optimus mostly managed not to look _too_ guilty about… whatever it was Megatron had been trying to get him to do.

Unfortunately, the plan didn’t go over so well.

"You can't seriously be considering sending Jack to another planet!" June gasped, horrified.

"He _will_ be coming with us," Megatron said.

"There is no need for threats, Megatron," Optimus chided.

"That was only a threat, it's not like I was threatening him," Megatron said, rolling his eyes. He paused and frowned. "Threat. Threat. _Threat_. Stars above, Optimus, this language is so restrictive."

"It is rare that any language puts such distinction between the fluidity of meaning behind a threat," Optimus said. "Even in Cybertronian, few would understand the difference between a threat and a _threat_."

Megatron thought about that for a long moment, then, with rising anger in his voice, said, "Are you trying to excuse the High Council's response to my address due to a _colloquial misunderstanding?_ "

"It did not help that they would not be able to tell the difference between a warning, a threat to their personal wellbeing, a threat to their livelihood, and a threat to their loved ones," Optimus said. "However, I do not believe you could have said anything to change their minds once we walked into the council chamber."

"Fascinating as this aside is," Fowler cut in, "does that mean you’ll be needing me to call in a spacesuit?"

Optimus nodded. "Cybertron’s atmosphere is unsuitable for human habitation."

"Is no one listening to me?" Juna snapped. "You can’t send Jack to another planet. He’s just a child!"

"Mom! I’m not a child!"

"Say that again when you’re twenty-one," June said.

"Nurse Darby," Optimus said. "I am afraid Jack is the only one who can help."

"Because of you!" June pointed a finger at Optimus. "Because you chose to _willfully endanger_ a child! Why would you choose Jack? Why not one of them?" She pointed at the other Autobots.

"Because Jack was the most suitable candidate," Optimus said. "I could not bring the key into Unicron’s spark and though Ratchet stayed behind, he is less of a believer in our gods than even humans who have not heard the name Primus, if you will forgive me for saying so, old friend."

"There’s nothing to forgive, Optimus," Ratchet said dryly. "I’m comfortable with my atheism."

June still didn’t look happy. Jack hugged her and she tried to smile for him.

"I'm coming too," Arcee said. "I'm not leaving Jack alone with you two."

"Thank you, Arcee," Optimus said.

"Yes," June said gratefully, "thank you."

"Are we done?" Megatron said. "Soundwave won’t wait forever."

"Yes, please prepare the communicator," Optimus said, securing Megatron’s cannon to his arm again.

Megatron keyed a code into the computer. Optimus straightened his shoulders and set his expression into something dark.

"Soundwave, this is Megatron," his impression was just as good as Megatron's. "There has been a complication with the fight against Unicron. I will need access to the Space Bridge to visit Cybertron to ensure his end has been met. And I will be taking Optimus with me."

* * *

Optimus and Megatron vanished while waiting for Fowler to show with Jack’s spacesuit. When they reappeared, Jack didn’t look too hard at any new scuffs they might have picked up.

Whatever happened to _Primes don’t party?_

The spacesuit was surprisingly heavy and slightly claustrophobic when the helmet blocked his peripheral vision. Sorta like his bike helmet, but also restricting — he couldn’t turn his head too far in any direction.

Jack said his goodbyes to June and Fowler, but was surprised to find all the Autobots were coming too.

"We’re going to make sure the Decepticons don’t try anything," Bulkhead explained. "They probably won’t leave Megatron stranded on Cybertron, but they’ve probably also got some kinda trap in the works, given they're ‘Cons."

The cave the Ground Bridge took them to was empty. Megatron led them through approximately half a mile of twisting passageways before they reached the Space Bridge.

Soundwave was waiting at the Space Bridge controls, the only Decepticon Jack had seen so far. Had they evacuated? Or was it just an off-shift for them? Or maybe they were in hiding, given the large number of Autobots. Or maybe they were hiding from Megatron? Jack had no idea.

Megatron gave Optimus an unsubtle elbowing to remind him that he was still pretending to be Megatron.

"Soundwave," Optimus said. "I did not tell you to come."

Soundwave’s visor flashed with something. Megatron stiffened as Optimus leant forward, confused.

"I don’t under—"

Soundwave’s tentacles lashed out, wrapping around Optimus’s arms and pinning them to his side. Then electricity shot through them.

Optimus collapsed. The Autobots readied their weapons. Megatron waved them down.

"That’s enough, Soundwave," Megatron said.

Soundwave relented and let Optimus go. He stalked over to Megatron and must have asked some kind of question because Megatron nodded.

"It’s why we must return to Cybertron," Megatron said. "But not something I wanted to broadcast, given the status of certain former members of our organisation."

Soundwave’s visor lit up again and Megatron laughed.

"But the Autobot side was poor," Megatron said.

Optimus got to his feet. He was still smoking a bit. Ratchet hurried over to give him a scan, muttering all the while about not having a good baseline.

Arcee and Bulkhead escorted Jack to the path in front of the deactivated Space Bridge. Bumblebee kept his weapons trained on Megatron and Soundwave, but more in a cautious way than an overt threat.

"Soundwave will stay here, to keep an optic on your Autobots," Megatron said. "I’m sure that won’t be a problem."

Three Autobots against one Decepticon, it shouldn’t have been a problem, given how flimsy Soundwave looked in comparison to even Bumblebee. Yet, the Autobots were uncomfortable and Megatron was too smug about the whole thing.

A reminder for Jack that as big and strong as the Autobots seemed to him, they hadn't won their war yet and it wasn't just because of Megatron.

Soundwave stepped up the console and calculations in Cybertronian started scrolling on the screen. Ratchet walked up behind him to look over his shoulder. It must've been the right coordinates because Ratchet didn't have anything negative to say.

"Brace yourself," Arcee told Jack.

With a roar like a tornado, the Space Bridge ripped open. Jack could feel the tug of it, even from this distance. It wasn’t dissimilar to the one time he’d been to the ocean on holiday and had to find his balance carefully against the tide while wading the shallows.

He walked forward, Arcee at his side, and into the greenish whirl. The Space Bridge made Jack's bones rattle down to the marrow. He gritted his teeth and set one foot after the other until, finally, he stumbled out the other side and onto a strange flat metal-like rock.

Cybertron was — well, it was a ruin. But it was still _so cool_ to be on an alien planet. Jack turned a slow 360 to take it all in.

"This is incredible!"

Arcee had stopped. Jack turned back and the smile fell off his face. Arcee looked… she looked heartbroken.

"Arcee?"

"This isn’t how I wanted you to see my home," she said, hundreds of lifetimes of grief etched into every word. "I’d forgotten… we tried so hard to save Cybertron, but, in the end, there wasn’t much left to save."

Optimus and Megatron emerged from the Space Bridge, discussing something in low voices.

"Which way?" Arcee asked, donning professionalism again.

"Oh, um…" Jack held up the key. It was glowing. He turned and the glow got brighter, then fainter. He pointed to where it had been brightest. "That way. I think."

Arcee frowned. "Not the direction I would’ve picked."

"No?"

"You’d think any holy business would be in Iacon. That’s where the Primal Basilica used to be," Arcee clarified at Jack’s confused look. "The key’s pointing the other way."

"Do you think we should go backwards?" Jack asked.

"No. I think we should trust you and the key," Arcee said. She frowned back at Optimus and Megatron, who were still bickering. "We have a heading," she called loudly.

"Good work," Optimus said, with a gentle smile that looked all wrong on Megatron’s face.

"Unless Vector Sigma lies within the Acid Wastes, that means we’re going to Tarn or another Decepticon city," Megatron said. "You won’t be able to walk there in the time it takes the human’s clean air to run out."

Optimus frowned — a much more apt expression for his current face. "I believe my vehicle mode can carry your frame."

"Or, you can transform and fly under your own power," Megatron said, smirking. "It’s not difficult, Optimus. You’ve dealt with differing vehicle controls before."

"All of them grounded," Optimus said. He shook his head. "Very well, but I will not accept any harm I do to your frame by accident being paid forward to our travelling companions."

Megatron laughed. "I’d much rather pay it back to you directly."

Optimus transformed — still hadn’t gotten old to watch — and his engine sputtered out a blast of shimmery heat. For a moment, Jack thought he had it, then Optimus spiralled out of control and crash-landed heavily at the base of an old statue plinth.

A laugh burst out of Jack before he could stop it. Thankfully Megatron paid him no mind and stalked over to where Optimus was extracting himself from the plinth.

"This might take longer than I thought," Arcee said grimly. "C’mon, let’s get a head-start. They can catch up."

"Could be fun to watch," Jack said, but he mounted Arcee when she transformed.

Jack hadn’t gotten bored of being on an alien planet by the time they reached the city limits, but as the key directed them into the vast, open, desert-like expanse surrounding the ruins, he remembered something.

"Hey, Arcee?" Jack said. "There’s something Optimus said, about his memory…"

* * *

Eventually, the roar of a truck and a jet reached them. Optimus was flying kinda wobbly, but he was still in the air. Megatron wasn’t following the road as well as Arcee was and kept skidding over the rough terrain. Maybe he’d gotten used to ignoring the ground when he flew.

"About time," Arcee called over.

"Hardly my fault," Megatron said. Then, sharply, " _faster_ , Optimus. You’re going to stall again."

Optimus ignited his thrusters and switched to a circling pattern above them.

"You’d think he’d never _seen_ a flight-capable vehicle mode before," Megatron grumbled.

"Like you’re doing much better," Arcee shot back, as Megatron took a sharp ridge of — rock? metal? metal rock? — to the undercarriage that he could’ve easily avoided.

"Mere scratches," Megatron said pridefully, but he shifted gears and joined Arcee on the flatter road anyway. "This was easier when I had treads and _proper_ armour."

"Treads? What, like a tank?" Jack asked.

" _Exactly_ like a tank," Megatron said. "Do you think gladiator-caste were allowed flight? It was two hundred years in the pits before I even won my transformation cog."

"I…" Jack realised he still knew very little about Cybertron’s history. There was so much of it and the Autobots didn’t like talking about the time before the war all that much. Or the time during the war. Or what they’d been doing on Earth before Jack knew them.

Sometimes they’d say _something_ , but it was never much.

Raf had suggested once that it might be for Bumblebee’s sake as much as theirs — from what Raf understood, Bumblebee had been born right before the war broke out and didn’t have any memories from before the fighting had started.

"How much has Optimus told you?" Megatron pressed, perhaps sensing weakness. "Do you even know he was my dearest friend, once?"

"I knew that!" Jack snapped. Okay, he hadn’t known that until half a day ago, but still. "And I know the basics."

"And what, pray tell, are _the basics?_ "

"Jack, drop it," Arcee ordered.

"Come now, Arcee." Megatron drew out her name. "I’m curious to hear some Autobot propaganda. It’s been some years since I last had the opportunity to extract information."

Arcee revved her engine. Jack stayed silent.

Megatron sighed. "It’s another hour to Kaon at this pace."

"I’m good with silence," Arcee bit out.

"Wait," Jack said, "Kaon? I thought we were going to someplace called… uh, Tern?"

"Tarn," Megatron corrected. "And no, our current heading is Kaon. I know the route to my city."

"Huh, fancy that," Arcee said, viciously amused. "Vector Sigma was right under your feet this whole time."

"A fact I’ll be sure to make use of once I’m in my own frame again," Megatron said.

* * *

Megatron tried to draw Jack and Arcee into conversation a few more times, but Arcee was good at the silent treatment and Jack was too awed at seeing a whole new _freaking planet_ to properly engage.

The key to Vector Sigma kept straight ahead. At least it didn’t appear to be trying any funny tricks — Jack had played video games, he knew some quests had weird things you needed to do to complete them.

Kaon was as much of a ruin as the rest of Cybertron, but something felt darker to Jack. Maybe it was just knowing that this was where Megatron and the Decepticons had come from.

Arcee’s engine quieted and she transformed.

"We should go for stealth," she said. "We don’t want to attract the wrong kind of attention."

"What do you believe will dare attack us with both Optimus and I travelling together?" Megatron asked, though he also transformed back into robot mode.

"In Kaon? I’ll give you three guesses," Arcee said with a roll of her eyes.

Optimus landed next to them and stumbled, still not used to Megatron’s body.

"The key is bright," he said. "We should go on foot to maximise our chances of finding Vector Sigma sooner rather than later."

Optimus spun around, sword unsheathing in an instant. Arcee and Megatron readied their weapons but were glancing around the ruins uncertainly.

"What is it, Optimus?" Arcee asked.

"There is something…" Optimus gave himself a shake and withdrew his sword. "My apologies, I believed that something was watching us."

"There probably was," Megatron said. "We have scouts on Cybertron. It’s likely that they have spotted our party and correctly made the call to not engage."

"I am not so certain," Optimus said, but didn’t elaborate further.

The key led them to an old colosseum with a statue of Megatron over the entrance. Jack looked at Megatron, wanting to know what Optimus would look like if he ever got smug, but Optimus’s face was displaying familiar sorrow.

"We should have retaken Cybertron by now," Megatron said quietly.

Optimus put his hand on Megatron’s back. "Megatron —"

Megatron shrugged him off and stormed into the arena floor.

"Always wanting the last laugh, Primus?" Megatron snarled into the empty stands. " _You will not take this from me!_ If we were angry — if we _rose up_ — it was because we had to!"

The ground started to shake and crack. Jack braced himself and both Arcee and Optimus hunkered down to ride out the earthquake. Megatron stubbornly stayed in the middle of the arena.

A structure pushed its way up from beneath the ground. Rock shattered and slid until a sloped doorway had fully risen. It didn’t belong in this ruined city.

As Jack approached, the lines in the door lit up bright blue, then the door swished open. It led down into a faintly glowing tunnel, deep within Cybertron.

"I’m guessing this is it?" Jack said.

"It would appear so," Optimus replied. "This way."

The tunnel had odd marks down it, not like the rest of the decorative markings. Arcee knelt down and ran her fingers through a scratch.

"Scraplets," she said darkly. "My best guess: they’re scouting ones. There’ll be a whole swarm in a week or two."

"Good thing we didn’t need to hang around," Jack said.

"Yeah, good thing."

Optimus and Megatron were getting ahead. Jack had to jog to keep up — not fun in a full spacesuit — until Arcee transformed back into bike form and let him hitch a ride.

"— so _sad_ all the time," Megatron was saying, as Jack and Arcee caught them up.

"You wanted it for yourself, once," Optimus said. "Think of this as a lesson of the burden it would have been."

"I never wanted the Matrix. I wanted the title of Prime," Megatron said. "The High Council didn't even _have_ the Matrix when I made my demands and they wouldn't have dirtied it with a lower-caste mech if they had, they made that crystal clear."

"Even so, from the Matrix's proximity alone, you should be able to feel a little of Primus’s love and gain a better understanding of the wider-spread Cybertronian suffering in the universe," Optimus said. "It should suffice as an example of the choice you were making when asking for the title of Prime."

"Unicron doesn't have this much influence," Megatron said. "I can think clearly with dark energon, unlike with this trinket in my spark chamber."

Optimus snorted, then looked surprised at himself for the noise. "Everything is bright and loud. I feel like I am on the edge of a panic attack and I have no way to calm down. Unicron's influence is _exhausting_ , Megatron."

"Yet clarifying."

"If you wish to give in to paranoia, perhaps."

The tunnel opened up into a huge, sepulchral chamber. Arcee pulled to a halt and transformed as soon as Jack got off.

Being the first human on Cybertron was one thing, being the first human in a place that was so obviously holy was another. Jack didn’t want to disturb anything, but the key glowed hot in his hand.

"Jack," Optimus said, making him jump.

"I’ve got the key," Jack said, then mentally kicked himself — of course, Optimus knew he had the key. "Uh, I’m guessing I should put it over there?"

"That is correct."

Jack walked into the middle of the chamber and put the key down. It resized until it slotted in perfectly. Jack barely managed to keep his feet when the platform slid back.

Optimus scooped Jack up once the platform stopped moving. Jack was about to ask _why_ when the platform tilted until it was vertical. Huh, could’ve been a nasty fall if he wasn’t careful.

"Behold, Vector Sigma," Optimus said in hushed tones.

Something huge and so blue it was almost white, rose in the centre of the chamber. Rings spun eternal, almost organic in their motion. Jack could stare at it all day.

It’d make an awesome screensaver.

"And now, we must wait," Optimus said.

"Because Primes never do anything when it suits anyone else," Megatron muttered nastily.

* * *

"Okay," Jack said, picking up the key when Vector Sigma finally disengaged and returned beneath the chamber, "I think it's ready."

"Wait." Optimus held up a hand to halt Jack. "Perhaps we should not do this yet."

"What? Why wait, Optimus?" Megatron asked. "Surely you want to reassure your precious Autobots that you’re back to normal?"

"Because I believe the Matrix did this for a reason," Optimus said. "Not to protect my memories, or even itself. But to end this war."

"By driving me to distraction?" Megatron’s blasters transformed out and _whirred_ up. "By saddling my spark with a god’s depression to make me give up? I will tear this relic out of my chest before I let you force me to bear it any longer."

"For you to feel Primus’s love."

"I don't care that Primus loves us — _it's not enough!_ " Megatron snarled. "Where was His love when the caste system was implemented? Where is His love while the war is still going on?"

"Primus loves all of us," Optimus said. "He sorrows when we fight, but He cannot control us, for to do so would not be love at all."

Megatron shuddered.

"I love you, Megatron," Optimus said simply. "I know this even as my memories are fading, it has always been true. I love you and I know it is not enough."

Megatron’s chest cracked open as a sob was wrenched from him.

"Enough, Optimus. _Enough_."

Optimus grabbed Megatron in a hug. The key started to buzz in Jack’s hand. He held it up and bright blue light shot out and flared around Optimus and Megatron. It got brighter and brighter, then white light washed everything out. There was a soft breeze then several heavy _clangs_.

Jack blinked back black afterimages. His eyes hurt. He kept still, not sure what had happened just yet, but worried that if he stumbled around trying to find Arcee he’d fall off the edge.

"Jack?" Arcee said, about thirty degrees away from the direction Jack thought she’d been.

"I’m okay."

Finally, Jack’s eyes cleared enough for him to see. Arcee was crouched, not too far away, looking like she’d had similar problems with getting her vision back.

Optimus and Megatron were both unconscious and flat on their backs. They sounded alive — Cybertronian bodies weren’t quiet unless they were in vehicle form and even then only some of the time — but beyond that, Jack couldn’t tell.

Arcee approached Optimus’s body.

"Where am I?" He groaned, sitting up.

"Optimus?" Arcee asked warily.

"Why did you call me that?" Optimus — Megatron? — said. "I'm sorry, have we met?"

Arcee lowered her pistols. "Who do you think you are?"

"My name is Orion Pax."

That was sorta good? Jack shifted his weight and Orion's eyes snapped to him.

"Is that an organic?" Orion asked, amazed. He knelt to peer down at Jack better. "I've never met an organic before. Do you have a name, little one?"

"I'm Jack." Jack looked at Arcee. "What do we do?"

Megatron groaned. Arcee raised her blasters again.

"We get ready to run," she said.

"Megatronus?" Orion started to make his way over to Megatron.

"Get back, Orion," Arcee warned. "I'll need you to take Jack and run while I hold off Megatron."

Orion looked at her, pure confusion on his face. Then he looked back at Megatron.

"I don't know what you believe to be true, but Megatronus is my friend," he said.

Megatron sat up and Orion offered him a hand. Megatron stared at it for a long moment, clearly still waking up, then let Orion help him to his feet.

"Optimus," Megatron said. Then he tilted his head, frowning at Orion. "No, Orion Pax."

A relieved smile broke over Orion's face. "Yes, Megatronus. Do you know where we are?"

Megatron started to laugh. There was a nasty edge to it.

"Orion!" Arcee snapped. "Get Jack out of here. Now!"

"Why bother?" Megatron said, something manic in his voice. "We've _won_. The war is over and the Autobots lost."

Arcee sucked in a sharp breath. "The Matrix —"

"You have no Autobot Prime now!"

Jack took a step back, awkward in heavy space boots. He was suddenly desperately aware of his limited oxygen supply and squishy, unarmoured body.

Megatron was taller — though it was hard to tell from human height — and his silver armour was edged with gold. The purple bits of his body had changed to a deep midnight blue, even the glow of his cannon.

"I am Megatron Prime," Megatron said. "And the Autobots are finished."

Orion stepped forwards, reaching for Megatron. He froze when Megatron stumbled back away from him.

"Megatron. Let me help. Please."

"You’ve _helped_ enough," Megatron spat. "No, Optimus. It wasn’t meant to be like this."

" _The duty of the Prime is more aptly called a burden_ ," Orion said softly. "From the data streams of Nova Prime. You do not have to bear this alone, Megatron."

Megatron screamed with rage then, while Jack cowered behind Arcee, flipped into his jet mode. His plating was more embellished like that too, but Jack couldn’t make it out in detail before he shot off down the tunnel.

"I'm kinda glad this suit comes with a diaper," Jack said shakily.

"Come on." Arcee transformed and pulled up next to Jack. "We need to get going before Megatron gets Soundwave to close the Space Bridge. Orion, follow me."

They reached the surface without issue — though Jack swore there were more scraplet trails than previously. The bleak, deserted city-ruin made Orion choke.

"Is this Kaon?" Orion asked. He sounded horrified.

"There's been a war," Arcee said shortly. "I'll update you as we drive."

* * *

"Is that… the Space Bridge?" Jack asked, squinting through the distorted curve of his helmet.

It looked like it, a bright mass of swirling blue, green, and white amidst the still ruins. Arcee slowed and transformed as they got closer.

"That's strange," she said. She activated her radio. "We should be in range. Ratchet, do you copy?"

" _I copy, Arcee_." Ratchet's voice crackled through the radio. " _Do you need assistance?_ "

Orion brightened at hearing his voice. Jack had guessed they'd been friends before the war from the way Ratchet had talked about Optimus's past — nice to have that theory confirmed.

"Has Megatron returned yet?" Arcee asked, frowning.

" _No. Has something happened?_ "

"Yes. And I think something else is about to."

As soon as she finished talking, Megatron burst out from a broken building and backhanded her.

Arcee went flying. Orion gasped.

Jack didn't move fast enough — damn these clunky space boots! — to avoid Megatron snatching him up in one hand.

Had his claws gotten sharper since Vector Sigma?

"What. Did. You. Do?" Megatron snarled.

"What?" Jack forced himself to stand straight, like Optimus was watching him. "I didn't do anything."

"Megatron." Orion stepped forward. "I don't think threatening anyone is going to help."

"This isn't a threat," Megatron snarled. "It's a question. What did you do to the Matrix?"

"I didn't do anything!" Jack insisted.

" _Liar!_ "

"Megatron!" Orion said firmly. "I know this must be confusing. Every account I've read of a Prime first receiving the Matrix reports them being overwhelmed by the depth of Primus's emotions. It is difficult to comprehend the intensity of a god's feelings, especially when they amplify your own."

Megatron shut his eyes and breathed out sharply. He looked… if Jack didn't know better, he'd say Megatron looked —

"Who are you grieving for?" Orion asked softly.

"No one." Megatron glared at Orion.

"You're sad about Optimus?" Jack said incredulously. "You hated him!"

Megatron tipped his hand, dropping Jack. Thankfully Orion was close enough to catch him before he fell the full four storeys and went _splat_.

"Megatron! No matter your disagreements, you should be careful," Orion chided. "Not everyone is as durable as you."

Megatron laughed bitterly. "A fact I am well aware of." He cupped Orion’s face. "I have won the fight and you are returned to me. I should be happy. And yet…"

"But you wanted Optimus dead," Jack said, feeling braver now he was out of Megatron’s clutches. "Didn’t you?"

"Of course I did."

It was such a bad lie that Jack took a moment to wonder if it was a clever double bluff of some kind. But that didn’t make sense.

"Everything I've read on the Matrix suggests that it brings inner peace," Orion said. "But you're acting erratically, Megatron. Is there a reason for that?"

"That human has done something," Megatron snapped.

"I doubt that," Orion said. "Forgive me, Jack, but your level of environmental protection is typical of a class delta planet, far too primitive to be able to alter a relic of the Matrix of Leadership’s power."

"Uh, sure," Jack said. "But… maybe the Matrix hasn’t been set up right, since I had to use the key to Vector Sigma and I’m just a human from a, uh, class delta planet?"

Megatron’s eyes flashed purple as he snarled. Orion backed up, holding Jack against his windscreen protectively.

"So he admits it!" Megatron snapped. Then his eyes went red again. "No. _Quiet Optimus!_ You had your chance!"

"Megatron, may I see the Matrix?" Orion said.

Megatron whirled and punched clean through a broken wall. He stopped and breathed heavily for several long seconds.

Jack was about to ask Orion to make a run for the Space Bridge when Megatron turned back.

"Be quick."

Megatron’s heavy armour shifted and parted. Blindingly bright light spilt out, burning purple and blue and gold onto Jack’s retinas. The Matrix looked so much more _alive_ than when Jack had last seen it.

"Oh." Orion froze, eyes wide, staring into Megatron's chest. "There's something else in your spark chamber."

"Don't touch that!"

"It looks like… dark energon," Orion said fretfully. "Megatron, how are you alive? Your spark won't be able to withstand Primus and Unicron's energies at once. They destroy one another and anything around them."

Megatron waved him off and closed his chest. "I can take it."

"It's not a question of strength," Orion said. "Your spark already flickers under the onslaught, I fear it will extinguish soon if nothing is done."

"Good," Arcee said grimly, rounding a pile of rubble. "Jack, are you okay?"

"Yeah."

Orion handed Jack back to Arcee and faced Megatron again.

"Pick one," Orion said. "Please, Megatronus, I could not bear it if you died."

"Of course you could!" Megatron snapped. "You’d like that Optimus, to have me dead and gone without having to stain your blades with my energon. Well, you’re not coming back, no matter how much I want to fight you — the Matrix is _mine_ and no Autobot is _ever_ going to touch it again!" He panted, eyes flickering purple and red, looking deranged. "I can’t stand this, Orion, it’s too much. I can’t. But you can’t have it and I _need_ the blood of Unicron. I won’t let Primus take you again, not when He can’t do more than _cry about unfairness_. What use is a god who does nothing but _hurt_ those I…" He choked. "I… I might not survive without dark energon, I _need_ it. I need it and I won’t force an uncaring trinket on you again, Orion. Optimus — don’t leave — no — I _can’t_ —"

"I would bear it for you," Orion said softly, interrupting Megatron’s rant with a gentle hand to his head.

"For Cybertron, perhaps," Megatron said. His shoulders fell. "I trust you. I… Be quick, I cannot keep my processor still for long."

He opened his chest again. Gold and blue and purple light shone out, swirling as erratically as the Space Bridge.

Arcee's transformed out her blasters but kept them lowered. She gave Jack a grim smile.

"Just in case."

Orion reached into Megatron's chest. Megatron was shaking. Slowly, Orion pulled the shard of dark energon out of Megatron's spark. It pulsed in a way Jack could only describe as _angry_.

Orion dropped it to the ground with a hiss and shook off his hand. The metal had warped where it had been in contact with the dark energon, bubbled and burnt.

"Sometimes I hate you, Orion Pax." Megatron shut his chest.

"How do you feel?" Orion asked.

"Calmer," Megatron admitted. "Warm." His normal red gaze slid to Arcee. "How long until your reinforcements arrive?"

"Like I’d tell you," she said fiercely.

"Hmph." Megatron stepped away, turning his back to them. Now that Jack had a slightly better understanding of the way _threat_ could be used differently, he wondered if this also meant something more than being a bit rude in human terms. "Go. Soundwave will not stop your escape."

Arcee powered down her blasters and transformed them away. She was looking between Megatron, the Space Bridge, Orion, and Jack, clearly trying to plan accordingly.

"Megatron, please." Orion stepped forward. "Let me help."

"Why would you want to?" Megatron asked, no emotion in his voice.

"Because…" Orion hesitated then placed his hand against Megatron's arm. "Because I love you."

Megatron lowered his head. "I know."

Emboldened now he hadn't been shrugged off, Orion reached down to clasp Megatron's hand in his own. Megatron looked at him.

"There are records within the archives," Orion said, gently encouraging, "data from past Primes. If the Iacon Hall of Records still stands, I can show them to you. Maybe they'll help you find peace with the Matrix."

"The Hall of Records was destroyed," Megatron said simply. He shut his eyes and let out an annoyed breath when Orion whimpered. "Soundwave was able to download much of the databases before the exodus. There hasn't been time to decipher them."

Orion’s face lit up. He was leaning into Megatron’s space in a way Jack wasn’t going to think too hard about.

"Um, Arcee?" Jack said quietly.

"I need to see how this plays out," Arcee replied. "You’ve still got air, right?"

"Twenty minutes," Jack said.

"We can wait closer to the Space Bridge if you want."

"Yeah," Jack said. "Yeah, that’d be good."

They moved over until Jack could feel the tide-tug of the Bridge. Arcee’s comm crackled to life again.

" _Arcee? What’s your status?_ " Ratchet demanded.

"Hold position," Arcee replied. "Shouldn’t be much longer."

" _That is_ far _from helpful!_ " Ratchet snapped. " _Do you need a medic or not?_ "

"Uh, why would you need a medic?" Jack said.

Arcee switched off her comm. "I couldn’t exactly say ‘I need backup to take down Megatron’ when Soundwave was listening in. This way I could get Ratchet with Bulkhead or Bee for backup without getting them having to fight their way through."

"Oh, cool."

"We’re fine, Ratchet," Arcee said, activating her comm again. "False alarm." She glanced at Orion and Megatron. "We’ll be through in ten minutes."

" _I’m holding you to that_."

"Wait here," Arcee said to Jack. "If anything bad happens you’re going to run through the bridge and get to Ratchet. Understand?"

"But I could —"

"No." Arcee cut Jack off. "If I get stranded here, fine, but you _have_ to get back to Earth. Do you understand?"

Jack clenched his fists, but the slow decrease of oxygen was making him worry too much to argue further.

"Fine," he said. "But… try to come back, okay?"

"Hey. The old rust-bucket hasn’t offlined me yet," Arcee said positively.

Arcee went over to Orion and Megatron. Orion welcomed her brightly, while Megatron narrowed his eyes in suspicion.

"Time to wrap this up," Arcee said. "The Space Bridge isn’t going to stay open forever."

"The Space Bridge will stay open for as long as I require it," Megatron said dismissively.

"What’s the destination?" Orion asked.

"Earth," Jack said, surprising himself. There was something very young about Orion that reminded Jack of Raf — though he knew Orion was already way old before he’d even gotten the Matrix. "It’s where I’m from."

"I would be delighted to visit your home, Jack," Orion said.

Megatron rolled his eyes and muttered something that sounded like ‘rain’, but made no proper comment to dampen Orion’s gentle smile.

"Orion," Arcee said, then paused.

"Let us _all_ return," Megatron said, "after all, I have to accept your Autobot surrender."

Arcee narrowed her eyes. "The war isn’t over yet. You’re just one mech."

"The war needs to end," Orion said. "Surely we can find terms of peace that suit everyone?"

Jack’s oxygen level indicator beeped at him. He felt his pulse skyrocket. He was going to suffocate on an alien planet because Megatron liked the sound of his own voice too much.

"Uh, ten minutes, Arcee."

"We won’t surrender," Arcee said fiercely, but she was backing up to get back to Jack.

"Megatron, please," Orion said.

Megatron made a noise like a car engine turning over, but twice as loud. "Fine. A ceasefire then. Provided I have Orion."

"And who do we get?" Arcee asked. "Starscream?"

"Airachnid or Soundwave."

Arcee looked surprised, then calculating. "Laserbeak."

"Not alone."

"Megatron, Arcee," Orion intervened, "I believe Jack is getting worried about the time."

"We can discuss this back on Earth," Arcee said.

Megatron smiled. For a moment Jack could’ve sworn that Optimus was back in control because that was _Optimus’s_ smile on Megatron’s face.

Huh, it was Megatron _Prime_ after all.

"After you," Megatron said.

As Jack stepped into the Space Bridge, he wondered how on Earth he was going to explain this to everyone back home.


	2. Chapter 2

**Notes for the Chapter:**

> Since I felt it was maybe a tad unfair to have just Jack’s pov in a week dedicated to MegOP, here’s a short bit of what Megatron and Optimus got up to in the closet while they were waiting for the spacesuit to be organised.

"Since when are you blushing and untouched?" Megatron groused, trying and failing to get Optimus to do anything other than just _stand there_.

Optimus tilted his helm, but up and _away_ rather than down toward Megatron. Damn his new height. What was the point in finding a bit of privacy only to _not_ do anything?

"I am not attracted to my own frame," Optimus said.

Megatron stared at him for a long moment. "What does that matter?"

Optimus grimaced — why must he insist on putting such ridiculous expressions on Megatron’s face? — and gave Megatron a firm push away.

"I am not as narcissistic as you," Optimus said. "It is strange to be looking at my own face."

" _Narcissistic_ ," Megatron scoffed. "It’s still me. Still my spark. What does it matter what I look like? Would you waste this opportunity if I’d had a rebuild?"

"That is different," Optimus said.

Megatron surged forward again. He knew his frame well enough to put pressure against all his wonderfully sensitive bits. Optimus made a strangled noise, but he was still resisting — like he’d resisted properly letting Megatron’s spike pressurise in front of the human.

The Matrix pulsed in Megatron’s chest. He gritted his denta and ignored it. Stupid old relic.

"Optimus, you agreed to a sparkmerge," Megatron said, calling upon a previously unknown well of patience.

"And I intend to go through with that," Optimus said. "There is no need for anything else."

"Have you no romance in your spark?" Megatron snorted. "A clinical merge is worse than a fight with no stakes. I’d spike you dry before I’d touch your spark cold." He stroked his hand up Optimus’s — his — chest. "Let me warm you up first."

Optimus was still hesitant, but if he'd meant _no_ or _stop_ he would have said so by now. _Strange_ just meant that Megatron needed to do a better job of distracting him.

Otherwise, it would be a _cold_ merge and that was just wrong.

"Close your optics," Megatron ordered.

Optimus complied and Megatron's spark spun brightly at the display of trust. It must be the Matrix again, Megatron could feel it trying to quiet his righteous rage with its smothering love.

He'd considered ripping it from Optimus's chest, but Optimus would likely do the same for Megatron's dark energon shard and he _needed_ that.

Megatron rubbed his servos over Optimus’s plating, firm and hard. There was no point in gentle brushes, Megatron’s armour was too thick for anything to reach his sensor-net, short of pressure that would buckle civilian plating. He followed the paths he used when self-servicing, the hitching in Optimus’s ventilations showing that no matter whose spark and memories were inhabiting Megatron’s frame, the metal-memory was still strong.

"Megatron." Optimus caught his hand before it could finish opening his codpiece.

"Do you want this, Optimus?" Megatron pushed. "Yes or no. Stop dithering."

"Yes, I do. However —"

"However nothing," Megatron said. "I highly doubt this will affect your opinion of me and you can hardly lose _more_ face in front of your Autobots, considering they saw us leave together."

" _However_ ," Optimus repeated. "My — your — sensors are wired more intensely than my own. I may need to pause occasionally."

Megatron didn’t feel like he’d lost any input compared to what he was used to. Perhaps a full bond with the Matrix dulled the senses.

All the more reason to ignore its useless little pulses against Megatron’s spark.

"Good to know it’s going to be even easier to reduce you to a puddle of mercury at my pedes," Megatron said. It didn’t feel like he’d said enough and he was compelled to add, "You can tell me to back off and I will. At least temporarily."

"Thank you, Megatron."

"Now," Megatron pulled his servo free and pressed it intently against Optimus’s — his — panels, "let me see what I look like from your perspective."

Optimus averted his optics again and released his — Megatron’s — panels. His — Megatron’s — spike pressurised into Megatron’s ready servo. Megatron curled his — Optimus’s — digits around it, enjoying, for once, being able to hold tightly without fear of cuts.

"Is everything okay?" Optimus asked.

Megatron blinked and reset his expression. "I’ve been told by more than one mech that my spike is considered… impressive. Yet it just matches my frame. _I_ am impressive, but given that, my spike isn’t moreso."

Optimus gave a short laugh, then looked startled, like he hadn’t expected to ever make such a happy noise.

Megatron scowled at him. Optimus cupped his head with a large clawed servo in a way that shouldn’t have been comforting, yet was.

"You are impressive," Optimus said. "You _and_ your spike. Remember what size of equipment most other mechs are working with."

"Speaking of other mechs’ equipment…" Megatron opened his — Optimus’s — panels and pressed his array against Optimus’s — his — thigh. " _Sensitive_ , Optimus. One might think you don’t get any use out of it."

"Please refrain from speculating about my interface habits," Optimus said.

"You know what one of my most-used fantasies is?" Megatron leant up to whisper. "We’re in the middle of a fight and you’re so overcome by the need for a good. Hard. Frag." He rocked his hips with the words, feeling the lazy crawl of charge dance between his array and Optimus’s thigh. "That you end up begging me for one. You haven’t been touched in centuries — too noble to ask your Autobots, too private to find a Neutral — but you know I’ll always _take care_ of you. You’re desperate, so desperate you overload the second I get my glossa on that hot, _wet_ valve of yours and still beg for more because it’s been _so long_ since you last got properly fragged."

Optimus’s cooling fans finally snapped on. Megatron ground his array down harder, his — Opitmus’s — spike starting to pressurise.

"So it’s a bit late to be asking me to stop speculating," Megatron finished. He stopped moving and was gratified to find Optimus had been following his movements and stopped rocking back a moment later.

"I…" Optimus looked dazed. Like it _had_ been centuries and he didn’t know how to revert back to a chargeless state.

"On the ground," Megatron ordered. "If you’re too out of it to make use of my frame’s strength, I’ll ride you instead."

He started to move back, but Optimus grabbed him by the hips and stopped him. A frisson of charge danced through Megatron’s struts.

Optimus’s frame _liked_ that.

"I have never been a selfish lover," Optimus said. Judging by his satisfied smile he knew those words made Megatron remember their previous encounters. "I do not intend to start being so now."

He turned them and pressed Megatron against the wall. Finally, _finally_ , he closed the distance and kissed Megatron. Sharp fangs caught Megatron’s — Optimus’s — lip and he kissed back harder, knowing the scent of energon would rev up Optimus’s — his — engines.

"Spike me," Megatron demanded. "Frag me through this wall or I’ll do it myself."

Optimus curled his claws around Megatron’s thighs and dug sharp claw tips into the transformation seams. As he lifted he pressed Megatron’s legs apart until he could feel the joints reach their limit.

" _Oh!_ " Megatron gasped as that motion made his valve automatically run its lubrication subroutine and his engine revved. _Optimus’s_ valve was reacting to it and, judging by how deep the relevant code was buried, Optimus had enjoyed that particular movement a _lot_.

But no, prim, perfect Prime wouldn’t get revved up during a fight like gladiator-caste did. The Matrix pulsed and Megatron spoke without thinking to ignore it.

"Do you like that, Optimus? How many times have I grappled you this way?" Megatron leant forward. His broken battle mask tried to shut as power diverted to his combat protocols at the implied threat, but the jagged edges couldn’t close and a background thrill of vulnerability rerouted his focus to interface. "How many times have I left you _wanting?_ If only you’d told me, I’d have taken care of you."

Optimus’s optics narrowed. He lined up his spike and pressed in steadily.

A warning flashed up on Megatron’s HUD, something about his valve capacity. He dismissed it with barely a glance, too interested in watching the play of emotions on Optimus’s — his own — faceplates as his spike sank deeper and deeper.

"Megatron!" Optimus was shaking. "Please —!"

Megatron overloaded.

Everything felt electric and liquid all at once. Megatron’s pleasure subroutine crashed and he spent several strange seconds with his emotional systems flailing as it tried to reboot. A short overload and not a particularly satisfying one.

He reset his vents and his optics and stared at Optimus in surprise.

"It really _has_ been a while for you, hasn’t it, Optimus?" Megatron said, even as the remnants of his overload sparked through his — Optimus’s — frame.

"I would rather not comment," Optimus said, which was a comment in and of itself.

Megatron readjusted his — Optimus’s — callipers one-by-one, loosening the death-grip they had on Optimus’s — his — spike. They weren’t far from their maximum capacity and Megatron decided to believe Optimus about how _impressive_ his spike was.

"Frag me, damn it," Megatron hissed. "Stop _dawdling_."

Optimus pinned Megatron against the wall harder and rolled his hips leisurely. The _tease_.

"You _like_ this," Optimus said, optics darting over Megatron’s — his — entire frame.

" _You_ like this," Megatron corrected. "I like _you_."

Optimus shuddered and he stopped moving. He was close to overload Megatron realised. He wasn’t usually so fast to the finish, but the combination of his spike getting to frag Optimus’s frame again combined with Optimus’s under-touched mind must be too much.

"What do you like in self-service?" Megatron asked. "Touch me like that and it’ll stall the immediacy."

"I…" Optimus heated up in embarrassment so much Megatron felt it in his valve. "That is private."

"You don’t have to tell me what you think about," Megatron said, "just how you touch yourself. Unless you _want_ to tell me."

Optimus let go of one of Megatron’s legs to bring his hand up and wrap it around Megatron’s throat. Megatron’s callipers clenched down without conscious input as heavy claws pressed against his cables and energon line.

"You know what I fantasise about," Optimus said brokenly.

"Me," Megatron said, half disbelieving.

"You."

"Frag me," Megatron said. "Hard and fast. You’ll want to keep going while you overload."

"But you’re —"

"Closer than you think," Megatron said. "You’re so _sensitive_ , Optimus."

Optimus flexed the hand around Megatron’s throat and used his other servo to gain the leverage to start thrusting properly. It was good. It was far better than Megatron had ever experienced with his own valve, but then he’d never allowed Optimus inside during their scant few dalliances before the war.

Something to remedy, once they were back to their normal selves.

Optimus fell into overload first, but the charge from his — Megatron’s — spike dragged Megatron over the edge with him. It was _good_.

This time his pleasure subroutines didn’t crash and let him ride out feeling with an arched back and flickering optics.

Before the charge had fully dissipated, Optimus opened his — Megatron’s — chest plates and exposed his spark. Purple light hit Megatron’s optics and he felt the absurd urge to flinch. The shard of dark energon looked… wrong. Next to Optimus’s spark, it looked poisonous, sickly. Like a piece of organic matter where there should be healthy metal.

It didn’t matter. Megatron needed it to win the war. No matter the cost to his frame in the long-run, it would be worth it to succeed now. He opened his — Optimus’s — chest plates, remembering at the last moment, annoyingly, that he had to first flip his windscreens out of the way.

"As much as I admire what the Matrix did to your frame, this part is purely frustrating," Megatron grumbled.

"I thought you liked windscreens," Optimus said. He frowned at Megatron’s spark. "The Matrix might get in the way."

" _Might?_ " Megatron echoed. "Do you mean to tell me you _haven’t_ sparkmerged since becoming Prime?"

Optimus looked away. "There have been precious few opportu—"

"This is going to offline you, isn’t it?" Megatron said. He tipped his helm back until it hit the wall. "Slag it."

"It is a distinct possibility," Optimus admitted. "I do not feel I can trust you to not take advantage of the situation, should it occur."

"We’ve got this far," Megatron said. The Matrix gave an odd stinging trill at Optimus’s accusation; Megatron revelled in its discomfort. "Would you like my word?"

"Yes. Please."

"Very well." Megatron considered for a moment trying for a tricky promise that he could easily exploit loopholes out of, but the idea didn’t appeal and he found himself wording a simple and effective pledge. "I will not do anything while you’re unconscious, should the merge render you so, except small measures to online you."

"Define _small measures_ ," Optimus said.

"What any reasonable mech might do to wake another," Megatron said. "A splash of liquid or a slap."

"Nothing that involves leaving this room."

"If you insist." Megatron looked at the rainbow bloom of sparklight dancing across their frames. "Shall we?"

Optimus pressed forward and the sparkmerge should have started immediately.

 _Should_ have.

Optimus leant back. "I do not understand."

"Try again," Megatron said.

Nothing. There was no merge. Even the usual static warmth of another spark was absent.

Megatron closed his chest plates. Optimus did the same. It felt _cold_.

"What does this mean?" Megatron asked, too emotionally raw to demand.

"It could be the Matrix," Optimus offered, sounding just as tender. "Its power is beyond the comprehension of most mechs, it might not wish to inflict its burden upon one potentially unprepared."

"And I thought all those jokes about frigid Primes were funny," Megatron said. "I can take it out —"

"No," Optimus said quickly. "It may be the cause of our predicament and removing it from the equation may ruin our chances of finding a fix."

In truth, Megatron didn’t want to remove it either way. His spark had been ready to merge and the unending flow of love from the Matrix was the only thing lending warmth to his spark now.

He _hated_ it.

"I feel a little off-balance," Optimus said. "I think I would like to stop now."

Megatron nodded. There wasn’t any point in continuing. The failure to sparkmerge had dissipated any lingering charge Megatron might have had.

Optimus eased out and let Megatron stand properly on his own — Optimus’s — two pedes. The room was brightly lit, but the lack of sparklight made it full of shadows in Megatron’s view.

There was no point in waiting around. The Matrix pulsed love and sorrow at Megatron again. He gritted his denta and turned away from Optimus. Taunting a few Autobots would put him back in a good mood.

Megatron opened the door and nearly tripped over Bumblebee, who was curled up in a ball next to the threshold.

"Scout?"

"Bumblebee?" said Optimus from behind Megatron, growing horror in his voice. "Were you… were you _listening?_ "

" _Ratchet wanted someone to keep an optic on you_ ," Bumblebee beeped. He sounded traumatised.

Good.

Megatron left Optimus to apologise to Bumblebee — a strange situation given the frame he held — and started back towards the central hub of the Autobot base. He noted with glee that he had scuffs of silver down his front and missing patches of paint. Not to mention the rather obvious scratches that had been left on his — Optimus’s — thighs that could only have been left by Megatron’s claws.

Time for some fun.

**Author's Note:**

> Come say hi over at [transformersvn.tumblr.com](https://transformersvn.tumblr.com) where I make Transformers visual novels.


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